class ElasticAPM::Metrics::CpuMem

def collect
  return unless sampler
  current = sample
  unless @previous
    @previous = current
    return
  end
  delta = current.delta(@previous)
  cpu_usage_pct = delta.system_cpu_usage.to_f / delta.system_cpu_total
  cpu_process_pct = delta.process_cpu_usage.to_f / delta.system_cpu_total
  @previous = current
  {
    'system.cpu.total.norm.pct': cpu_usage_pct,
    'system.memory.actual.free': current.system_memory_free,
    'system.memory.total': current.system_memory_total,
    'system.process.cpu.total.norm.pct': cpu_process_pct,
    'system.process.memory.size': current.process_memory_size,
    'system.process.memory.rss.bytes':
      current.process_memory_rss * current.page_size
  }
end

def initialize(config)
  @config = config
  @sampler = sampler_for_platform(Metrics.platform)
end

def sample
  @sampler.sample
end

def sampler_for_platform(platform)
  case platform
  when :linux then Linux.new
  else
    warn "Unsupported platform '#{platform}' - Disabling metrics"
    @disabled = true
    nil
  end
end